War for the Planet of the Apes: What Weta created will astound you
Hair. It's enough to let down any great movie.
Digitally creating hairy characters running around in snow and water has never been quite so well-translated on the screen – until now.
Thousands upon thousands of hours were spent scrutinising over billions of tiny but very important hair strands for the latest instalment of the Planet of the Apes movie series – War for the Planet of the Apes.
The detailing process was a major turning point for Wellington's Weta Digital.
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Artists were faced with some major challenges: how does fresh snow mix with fur? How does snow stick to fur? How does it clump on? How does it fall off? How does it react as the apes walk through the snowy environment?
The team realised they needed to start with understanding how hair captured light.
Weta's visual effects supervisor Dan Lemmon says his team overhauled the entire hair department and designed an entire new computer programme, called Manuka, that could model the way that light moves through a scene – so it is more accurate to physics and the way the real world works.
Manuka, a rendering engine, is a computer's version of taking a photograph.
Lemmon says the computer draws each pixel and shoots out virtual rays onto the scene to figure out what colour it should be based on the light.
"The process on some of our bigger shots can take up to, or in excess of, a thousand hours for each frame," he says.
"There's 24 frames in a second and 60 seconds in a minute and 130 minutes in the movie, and so you do that math and you realise to render a whole scene literally takes thousands and thousands of years of computer power to make the whole movie," he says.
The second thing they did was rebuild their hair material model, or their idea of how a hair looks like, inside of that rendering engine.
"Before, we had every hair as a single cylinder and now we moved to what we call a multi-core material model where we assimilate the very layers of the hair, the cuticle with all the scales, the cortex with the pigmentation, so as light moves through and inside of every single individual hair.
"The way that it behaves optically is a lot more accurate to physics.
"Our characters have between one and 12 million hairs on them depending on which character it is and there are tonnes, literally millions of hairs, and then, inside each hair there are millions of calculations being done to move that light through the hair and scatter onto that hair volume, so it's an incredible and staggering calculation.
"It all adds up to an image, a picture that's a lot more realistic and believable than we've ever been able to achieve in the past."
Producer Peter Chernin says working with hair and fur is incredibly complex.
"Wet fur is one of the hardest things to do digitally and snow on fur is another level on top of that. What's been fun is that a huge number of special effects people got into their jobs because of the original  Planet of the Apes movie, though it was done with makeup and costumes, because it was so imaginative – and now they are really pushing the state of the art of CG animation to create images such as an ape on horseback in the snow, which is extraordinary," Chernin says.
"Weta has allowed us to do things that could only exist in pure imagination before," adds Dylan Clark, another producer on the film.
Lemmon isn't a hair expert at this stage, but admits he know's a bit more than the Average Joe about the topic.
"I've definitely probably looked at hair in more detail than most people would. There's still so much more to learn. It's like any area of science you get into, it's like, 'oh my god, there's a whole world of it that's just ready to be unpacked'," he says.
From observing and creating digital avalanches to digitally knitting Bad Ape's hat and jacket, Lemmon has unpacked a whole world of jaw-dropping visuals.
Due to the moving states of the snow, avalanches are usually too difficult to translate believably on screen.
"It's a fun and different sort of problem to sink your teeth into," Lemmon says.
"Avalanches are really interesting. They have properties about them that somehow behave like gas. You'll have those expanding clouds – they almost behave like a liquid, as the snow loosens up it will run over rocks and sort of explodes like white water as it flows down a valley. And in some ways it behaves like a solid – those big chunky pieces that actually have rocks in them and they knock over trees and take things down.
"It's this really sort of multiple-state, complicated phenomenon that's pretty tough to create realistically."
Don't take the clothing for granted in the movie, either.
Bad Ape's hat took four weeks to digitally knit .
"We tried to avoid having to knit the whole thing, but in the end we just went for it," Lemmon says.
"The yarns in the hat and the yarns in the top of jacket were actually modelled in a full pro-knit pattern and we properly knitted the arms together, and then, on top of that yarn, we added a bunch of fuzz as well and we added fuzz on the nylon part of his jacket, just to give it the right tactile effect to the point where there was more fur on his hat and jacket than there was on the rest of his body.
"That, in particular, was a bit of experimentation.|
Lemmon says there will always be something that can be improved as the team learns more, but nevertheless he couldn't be more proud of the movie and the work his team made.
"We have to make everything. We have to figure out how to make it work inside the system," he says.
"There's a lot of stuff that, if you were making the wardrobe or you were making the props, there's a certain amount of realism that you get for free because it's real stuff that exists in the real world, so we have to fabricate manually.
"I think it's a great film and I'm really excited to see how the rest of the world embraces it. There are absolutely things I've learned that I'll take into the next show I do and continue to improve on, but I think as a piece a work it holds up pretty darn well."
War for the Planet of the Apes (M) opens in New Zealand cinemas on July 12.